Endoscopic video systems are known, by way of illustration, from DE-A-32 04 316. The endoscopic video system described in this printed publication is provided with an illumination fiber bundle and an imaging fiber bundle. The illumination fiber bundle guides the light of an illumination device to a light exit aperture at the distal end of the endoscope. An endoscope lens disposed at the distal end of the endoscope images the object field illuminated by the illumination device. This image of the object field is transmitted by the imaging fiber bundle to an electronic image recorder which is disposed proximally and can be, by way of illustration, a vidicon tube or a charge-coupled device such as a CCD chip.
Hitherto fiber bundles which are "ordered" and respectively "coherent" have been employed as imaging fiber bundles in endoscopes. What is meant thereby is that the light entry surface and the light exit surface of each optical fiber of the fiber bundle is located, always in relation to the same position, on the lens plane (i.e., image plane of the endoscope lens) and the image plane (i.e., lens plane of the image recorder).
However, the production of ordered fiber bundles is complicated and therefore expensive. In particular, waste is quite high because, on the one hand the individual fibers break or are otherwise damaged during production, and on the other hand sorting the individual fibers is not always optimal.
In the endoscopic video system known from DE-A-32 04 316, the imaging fiber bundle is an incoherent bundle. What is meant thereby is that the entry-side end and the exit-side end of each fiber are not disposed at the same relative position in the image plane of the endoscope lens and in the lens plane of the image recorder so that the transmitted image in the lens plane of the image recorder is "mixed up". With regard to this, reference is made to page 7, lines 7 to 14 of DE-A-32 04 316.
A decoder, or an image processing unit, corrects the "incoherent" image signal from the image recorder in such a manner that the image is "coherently" represented, by way of illustration, on a monitor.
In the generic endoscopic video system known from DE-A-32 04 316, the relative orientation of the lens-side ends of the incoherent fiber bundles with respect to the image-side ends prior to inserting the fiber bundle into the endoscope is fixed permanently, or "once and for all". (cf. page 8, lines 26f of DE-A-32 04 316).